Slab and building construction



July'19, 1932. c. F. DAVIS SLAB AND BUILDING CONSTRUCTION Filed April 7, 1931 6 Sheets-Sheet 1 gwwmtoz y 1932- c. F. DAvis 1,867,615

SLAB AND BUILDING CONSTRUCTION I Filed April 7, 1951 e Sheets- Sheet 2 6 Sheets-Shet 3 c. F. DAvls SLAB 'AND BUILDING CONSTRUCTION Filed A i-il 7; 1931- Jul 19, 1932.

Jfily :19, 1932. c. F. DAVIS SLAB AND-SUILDING CONSTRUCTION Fiied April 7, 1931 6 Sheets-Sheet 4 C. F. DAVIS SLAB AND BUILDING CONSTRUCTION July 19, 1932.

Filed April 7,1951 6 Sheets-Sheet 5 C. F. DAVIS Jul 19, 1932.

SLAB AND BUILDING CONSTRUCTION Filed April 7, 1951 6 Sheets-Sheet 6 dttouwq Patented July l9, W32

CLARKE F. DAVIS, 01? WESTFIELD, NEW JERSEY, ASSIGNOR TO STRUCTURAL GYPSUM CORPORATION, OF LINDEN, NEW JERSEY, A CORPORATION 015 DELAWARE SLAB AND BUILDING CONSTRUCTION Application filed April 7, 1931. Serial No. 528,302.

My present invention relates to a building construction system and to precast slabs of plastic material used therein.

In the building art it has become common practice to erect a skeleton framework of metallic beams and to support thereon or therefrom floors, ceilings and roofs composed of precast slabs of plastic material, such as gypsum or the like, or to construct such decks of a poured-in-place monolithic body. Prior constructions of this type have not been entirely satisfactory, due to the fact that diiferent conditions required a large number of dilferent types of slabs where the precast variety is used, and a poured-in-place construction required the use of forms and reinforce ments which were expensive both from the standpoint of initial cost and also from the standpoint of erection and labor difficulties.

The principal object of the invention, therefore, is the provision of a building construction system which will require a minimum variety of precast units, these units to,

have such flexibility of application to varying building conditions that they may be as near universal as possible.

Another important object of the invention is the provision of such a system in which the individual units may be factory cast, with minimum labor difliculties, and preferably on automatic machinery, so that in the field they may be assembled into the building construction with the minimum amount of fitting and by unskilled labor.

Another important object of the invention is the provision of a system in which a much lighter slab construction may be used than heretofore, and in which a concrete or cinder fill commonly used in floor constructions will so co-operate with the slab units as to form in effect not only a monolithic structure but also will contribute materially to the ultimate or total strength of the floor or roof construction.

It is still another object of the invention to provide a building construction as above described which will have the requisite strength and yet because of lightness will permit of a matcrlally lighter steel framework being used than has been possible heretofore, so that in figuring building costs, the reduction in the amount of steel used, the reduction in cost of the precast units and the reduction in the cost of erection will all contribute to a cheaper total cost, without sacrificing strength or as fire-proofing qualtities while at the same time making possible erection in minimum time and with minimum difiiculties.

To this end, the invention contemplates a building construction which includes a steel co framework comprising vertical sustaining members and main horizontal supporting elements extending therebetween so as to form substantially rectangular bays. Co-operat ing with the main supporting elements are to junior or intermediate beams preferably spanning the distance between main supporting elements so as to break up the entire bay into a series of smaller bays, sections or panels. It is contemplated that the spacing of to the junior beams or junior supporting elements will be according to apredetermined arrangementdependent upon the length of certain composite precast slabs which will be supported between junior beams or main supporting elements, or both. Thus, by providing a small variety of lengths of composite precast units, a large Variety of difierent buildmg constructions embodying bays of modated. It is contemplated that between the spaced apart composite precast units, machine manufactured precast filler units of standard dimensions will be used supported different sizes may be expeditiously .accomeither directly upon the composite units or between a composite unit and a junior supporting element or a main supporting element. Thus by providing the composite units in varying makes,-these standard precast filler units may constitute as high as W of set cementitious material, sothat when a m a concrete or cinder 'filI'is poured above the entire floor or roof, as the case may be, this poured fill will interlock and bond with the projecting portion of the metallic structural member to form not only a monolithic upper surface and thus bond all of the precast units together, but this fill will also contribute materially to the ultimate or total strength of the floor or ceiling construction.

It is contemplatedthat the individual precast units will be constructed of such form and shape that the lower surfaces thereof will be substantially flush, so that plaster may be applied directly thereto where a beamed ceiling is desired, or at the same time these precast units may support a ceiling construction of any desired type such as metal lath and plaster which will extend entirely below the beams or supporting members, so as to form an entirely flat ceiling not beamed.

The invention further consists in the novel arrangement, combination and construction of the system shown and described, and also of the individual precast units more fully hereinafter described and embodied in the above building construction.

In the drawings- Fig. 1 is a perspective view of a floor constructed according to the above invention in various stages of completion, for the sake of clearness.

Fig. 2 is a plan view of a bay embodying the construction of Fig. 1.

Fig. 3 is a perspective View of one of the I precast composite slab units.

Fig. 4 is an end view partly in section of the slab of Fig. 3.

Fig. 5 is a fragmentary side elevation showing one end of the slab of Fig. 3.

Fig. 6 is an assembled sectional view of a modified composite precast unit showing the manner of laying filler units thereon.

Fig. 7 is a perspective view of still another modified form of composite-unit in which no metallic structural members are embodied.

Fig. 8 is a fragmentary sectional elevation showing the manner of erection of the slabs of-Fig. 7

Fig. 9 is a perspective view of one of the precast filler units. 1

Fig. 10 i is a partial sectional elevatlon showing the manner of reinforcing the filler unit of Fig. 9. Q

Fig. 11 isa perspective view of a modified filler unit.

Fig. 12 is a sectional view showing the manner of use of composite and filler units and their relation to a supporting element in a beamed ceiling and floor construction.

Fig. 13 is a sectional view along the line 1313 of Fig. 12.

Fig. 14 is a view similar to Fig. 12, in which composite units, fillerunits and a poured-inpla'ce construction is used.

described hereinafter.

Fig. 15 is a sectional' view along the line 1515 of Fig. 14, showing in addition thereto a supported ceiling.

Fig. 16 is a perspective view of one of the ceiling supporting hangers.

Referring now to a preferred embodiment of the invention as above illustrated, I have shown at 1 a vertical sustaining element which may in this case be an I-beam of suitable dimensions to which there are attached four main horizontal supporting elements 2 extending therebetween to form or intermediate supporting elements 3 will of course, be spaced apart predetermined distances, dependent upon the type of construction being erected, regardless as to Whether a floor or roof construction is under consideration. 4

In Fig. 3 there is shown what I shall term a composite precast unit 1, consisting of side structural members 5 extending longitudinally of the slab and having cast therebetween a body of cementitious material 6 such as gypsum or the like. either with or without fillers such as sawdust or wood chips. As shown in Figs. 3 and 4, the structural members 5 are essentially channels having a double lower flange 7, one side of which is entirely embedded within the body of cementitious material, the top of the'other flanges being exposed or free from such set material. Thus, the members 5 are rigidly bonded and secured to the set material 6. Obviously other specific forms of structural members such as Zs, P5 or bulbTs may also be used. It is desirable in a floor construction embodying a concrete or cinder fill to permit the upper flange 8 of the structural members 5 to project above the upper surface of the set plastic material 6 for a purpose to be more fully Where found necessary, a lateral reinforcing member 9 may be provided, the main body of which extends substantially at or above the lower double flange? of the structural members 5, being bent, back upon itself to form a loop 10, and these ends extending downwardly beneath the double flange 7 and outwardly toward the side edges of the material 6. Such a reinforcement lends strength to these precast composite unitswhere additional strength is desired, but this will ordinarily not be found necessary.

In the preferred form, the structural members 5ex'tend beyond the ends of the body of set plastic material 6 and these projecting ends are adapted to rest upon and be 'sup the arrangement of junior supporting elements 3 of these precast composite units 4 may be used to satisfy all existing building construction conditions.

Precast filler units are shown in the preferred form in Fig. 9 as consisting of a main body of cementitious material such as gypsum or the like 12, the thickness of such body being substantially the thickness of the cementitious material 6 in the composite units 4. The body 12 of the filler units is provided with end flanges 13 adapted to rest upon and be supported by one of the bottom flanges 7 of the composite units. Thus, it will be seen that the upper and lower surfaces of the set cementitious material of both the composite and filler units are in substantially the same planes respectively.

It is contemplated that these filler units are to be made on automatic machinery requiring the minimum amount of labor so as to produce the same cheaply, and while they may be made in different lengths, yet ordinarily this will not be found necessary, due to the factthat as the bottom flange of the members 5 of the composite units and the flange 13 of the filler units are both of 'substantial extent, a certain amount of leeway or adjustment may be made therebetween so as toaccommodate any inequalities in the distance between main supporting elements. This is principally true in such a construction as shown in Fig. 2 where a number of composite units are used between main supporting elements.

In order to lighten the filler units and to save material, they may be cored as at 14 though in some cases solid units may be desired. It will also be found desirable to provide these filler units with longitudinal reinforcements, shown at 15, which extend through or near the tension zone of the slabs and extend upwardly into the end flanges 13. As shown in Fig. 10, the reinforcement 15 is so located within the flange 13 that a portion of the reinforcement is actually at the under surface of the flange 13, as at 16, and this end is then bent back upon itself reentrantly into the body of the slabs as at 17. Thus. when the filler units are supported at their ends on the flange 7 of the structural members 5, there is a metal to metal contact between the reinforcement 16 and the flange 7. a desirable condition. It is contemplated that a plurality of these reinforcements may be provided in each filler unit, being preferably arranged between and outside of the core holes 14.

By reference to Fig. 2, it will be seen that a series of such filler units are dropped down between the spaced apart composite units to fill that space. In certain circumstances, it may be found that these filler units will completely fill that space, but in others, the total sum of the width of the filler units may be not equal the distance between the upper flange edges of either the junior supporting elements or the main and junior supporting elements. This is the case in Fig. 2. To take care of this exigency, a modified form of filler unit is provided as shown in Fig. 11. This, to all intents and purposes, is the filler unit of Fig. 9, but is provided longitudinally with breaking grooves 18 both on the bottom or one .face of the slab and at the under portion of the over-hanging flange 18. These breaking grooves may be placed at such positions in the slab as to permit the entire slab to be readily broken in half or in quarters, or in other proportionate parts as desired. One of these broken parts is indicated'at 19 and is shown inserted between a complete unit 12 and a junior supporting element 3, so that the gap between the composite units and the main and junior supporting elements is completely filled with precast units. This is also illustrated in section in Fig. 13. It is desirable to so arrange the reinforcing rods 15 in the modified form of filler unit shown in Fig. 11 so that when the slab is broken into sections, each section will contain its own reinforcement.

In many cases, it is necessary to erect soil, water or gas pipes and electrical conduits vertically between floors and these are ordinarily placed as close to the main sustaining elements 1 as possible. Such an arrangement, however, breaks the geometrical continuity of the space to be filled adjacent such a vertical sustaining member. In such case, it may be found desirable to saw a section out of a filler unit or units to accommodate these irregular ities and to permit the filler units to fit nicely around these pipes or obstructions. As the filler units are made of gypsum either with or without fi ars such as wood chips,they may be readily sawed without difliculty, the reinforcements therein being severed by means of a hack-saw where this is necessary. However, where these irregularities exist to such an extent as to make'it undersira-ble or inexthe composite units or thetop of a supporting element, or both, and then a grout or plastic mix poured upon the form to the desired level. Such a construction is shown at 21 in Figs. 14 and 15. This expedient not only provides an efficient covering surrounding any irregular beam or pipe, but serves to join the precast units as a monolithic construction.

The herein described building construction is particularly adapted for use with floors where a concrete, cinder or gypsum fill is to be placed on top of the precast unit construction. Such a fill is shown at 22 in Fig. 1 and in dotted lines in Figs. 12, 13, 14.- and 15. This fill, of course, is placed after the precast units have been erected. Due to the fact that the upper flange or top 8 of the structural memhers 5 of the composite units project upwardly a substantial distance above the top of the body 6 of cementitious material, the-plastic fill upon setting bonds therearound and thereto. As the filler units are supported either directly upon the composite units or upon t e supporting elements, this fill in efiect sustains a great deal of the load not only of the dead weight of the units but of the dead weight upon the complete floor. This construction, therefore, permits of a much lighter precast system and steel construction than has been possibleheretofore, all of which contributes materially to the reduction of total cost of the building, without sacrificing in any way the fire-resisting qualities of the structure or the load which the floor-"may sustain.

From an inspection of Figs. 1 and 2, it will i be noted that the tops of the main and 3u'nior supporting elements may be exposed between the ends of the composite units and between the lateral edges of the filler units. In this case the cinder, concrete or gypsum fill 22 completely covers these exposed portions of the supporting elements and thus fire-proofs the same from above.

As is usual, a floor of any desired type may be laid directly upon the fill 22, as shown at It will be apparent from an inspection of Figs. 12, 13 and 14 that theabove construcelements, these beams are effectively fire"v proofed. The haunch slabs may receive tion provides a floor having the bottom surface thereof in substantially the same plane. This enables the contractor to plaster directly upon the bottom surface thereof, without the interposition of lathing or the like and without the addition of other constructional materials to provide a flat ceiling. By providing haunch slabs 24 erected upon'the bottom flanges of the main or junior supporting plaster in the same manner as the under surface of the floor'so as to produce a beamed ceiling.

Where a beamed ceiling is not desired, but on the contrary a ceiling is wanted which extends below the bottom of the supporting elements or beams, the construction shown in Figs. 15 and 16 may be resorted to. This consists in dropping down between the lateral sides of the filler units a strap 25 of any desired length, dependent upon the depth of the supporting element or the distance between the floor and ceiling. This strap 25 may be provided at the top with a hole 26 already punched and adapted to receive a pin 27 which will rest on top of the filler units, the lower end of the strap having a hole 28 punched in the field at the desired point and adapted to receive a pin 29 for the purpose of supporting a ceiling 30 of any desired type. Obviously the upper projecting end of the strap 25 is buried in the fill 22 and the lower end of the strap may be effectively covered by plaster or the like.

In some instances, it may be found desirable to provide a floor construction in which composite units will be used having a body of cementitious material therebetween which does not extend below the bottom flange of such units. Such a construction is shown in Fig. 6, the body of cementitious material being indicated at 31. In this case, the bond between the, structural members 5 and the cementitious material 31 being materially less. than that in the construction of the slab of Fig. 4, it maybe found desirable to provide bonding elements between thetwopartswhich may conveniently consist of a spike or the like 32 penetrating the web of the structural member 5 and having its end bent over as at 33. This instrumentality will efiectively prevent accidental detachment between the structural members and the body of cementitious material during shipment. Obviously such a method of bonding or tyin may be also usedwith the composite unit 0% Fig. 4. This modified form of composite unit is also pro- .vided with the upwardly projectin flange 8 adapted to bond and be interlocke with the poured fill as in the case of the preferred construction. v

With the modified unit shown in Fig. 6, filler units shown generally at 3 1 may be used. and these will consist of simple rectangular slabs either with or without reinforcements and with or without core holes.

Where a floor or a roof construction is designed tobe used without a poured fill and it is desired to use'precast units of such requisite strength as to maintain the load without assistance or contribution from the fill, the body of cementitious material 6 of the unit shown in-Fig. 4 may extend entirely to the top of the structural member 5 and the filler units 12 be proportionately thickened or, on the other hand, the composite unit of Figs. 7 and 8 used. This unit may be constructed of concrete or the like and consists entirely of a set body of material 35 having an overhanging upper end flange 36 and a lower exported upon the supporting elements as in the case of the unit of Fig. 3, and the latter to support the filler units as in, the preferred form. This modified composite unit may also be provided with core holes as desired to lighten the same, and with longitudinal reinforcing rods arranged in the manner of that shown in Fig. 10. Lateral reinforcements may take the configuration shown at 38 in Fi 8.

fhe invention has been shown and described with particular reference to several specific embodiments, yet obviously I do not wish to be limited thereto but the invention is to be construed broadly and limited only by the scope of the claims.

I claim:

1. As an article of manufacture a composite slab comprising two spaced apart metallic structural members, and a set mass of plastic material therebetween, said mass extending below the bottom of said members and terminating short of the top thereof.

2. As an article of manufacture a composite slab comprising two spaced apart metallic structural members, each having a base, a set mass of plastic material between said members, the base of each element having set plastic material above and below the same.

3. A composite slab comprising two spaced apart metallic structural members, and a set mass of plastic material therebetween, said mass extending below the bottom of said members and terminating short of the top thereof, and a metallic reinforcement embedded in the set material and extending above and below the bottom ofithe structural members.

4. A composite slab comprising two spaced apart metallic structural members each having a channel defined by a vertical web and a top and bottom flange projecting substantially at right angles thereto, the two members being arranged with their channelled portions facing each other, and a mass of set plastic material between said members, extending below the same but terminating short of the top flanges thereof.

5. As an article of manufacture a composite slab comprising two spaced apart metallic structural members, each having a head atthe top thereof, a mass of set plastic material between said members, the head of each member projecting above the body of set material.

. 6. A composite slab comprising two spaced apart metallic structural members, and a set mass of plastic material therebetween, said mass extending below the bottom of said members and terminating short of the top thereof, the metallic members being of great er longitudinal extent than the body of set material.

7. As an article of manufacture a compos lic structural members, and a set mass of plastic material'therebetween, said mass extending below the bottom of said members and terminating short of the top thereof, the metallic members being of greater longitudinal extent than'the body of set material, each end portion of each of said members being free of set plastic material.

8. As an article of manufacture a. composite slab comprising two spaced apart metallic structural members, and a set mass of plastic material therebetween, the top thereof being below the head of the structural members.

9. As an article of manufacture a composite slab comprising two spaced apart metallic structural members, each having a web, and a head at the top thereof, a set mass of plastic material between the members, the said heads and a portion of each of said Webs projecting a'substantial distance .above the top of said mass of set material.

10. A composite slab comprising two spaced apart metallic structural members, and a set mass of plastic material therebetween, the top thereof being below the top of the structural members, and an anchor projecting through a structural member and into the set mass, said anchor terminating short of the opposite structural member, said anchor comprising a spike with its end turned at right angles to the spike body.

1 1. A building construction including spaced apart supporting elements, spaced apart composite slabs at ri ht angles thereto, each slab comprising longitudinally extending metallic structural members with a mass of set plastic material therebetween, the body of which extends below the bottom of said members, the ends of said structural members resting on and being supported by the supporting elements, and filler slabs between the spaced apart composite slabs and resting on the sides thereof.

12. A building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extending metallic structural members with a mass of set plastic material therebetween, the body of which extends below the bottom of said Elle members, the ends of the structural members resting on and being supported by the su porting elements, and filler slabs between t spaced apart composite slabs and resting on the sides thereof, each of said metallic structural members having a portion projecting upwardly above the top surface of said set plastic material, and a set plastic fill extend; ing over the joint between a composite slab and a filler slab, the upwardly rojecting portion of each structural mem r being embedded in said set fill.

13. A building construction including spaced apart supporting elements, space apart composite slabs at right angles thereto,

each slab comprising longitudinally extend-- ing metallic structural members with a mass of set plastic material therebetween, the body of which extends below the bottom of said members, the ends of the structural members resting on and bein supported by the supporting elements, ller slabs between the spaced apart composite slabs and resting on the sides thereof, each of said metallic structural members having a portion projecting upwardly above the top surface of said set plastic material andextending toward the upwardly projecting portion of its neighbor, and a set plastic fill extending over the joint between a composite slab and a filler slab, the upwardly projecting portion of each structural member being embedded in said set fill. 14. A building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extending metallic structural members with a mass of set plastic material therebetween, the body of which extends below the bottom of said members, the ends of the structural members resting on and being supported by the supporting elements, and filler slabs between the spaced apart composite slabs and resting on the sides thereof, each of said filler slabs having a side flange, a metallic reinforcement in said slab extending into said flange and near the under side thereof, the side flange of the filler slabs engaging and being supported upon the composite slab. I

15. A building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extendin metallic structural members with a mass o set plastic material therebetween, the bod of which extends below the bottom of sai members, the ends of the structural members resting on and being supported by the supporting elements, and filler slabs between the spaced apart composite slabs and resting on the sides thereof, the top and bottom surfaces of the set plastic material between the structural elements being in substantially the same plane as the top and bottom surface of the filler slabs respectively.

16. A building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto,

each slab comprising longitudinally extending metallic structural members with amass of set plastic material therebetween, the body of which extends below the bottom of said members, the ends of the structural members resting on and being supported by the supporting elements, and filler slabs between the spaced apart composite slabs and resting on the sides thereof, each of said metallic structural members having a portion projecting upwardly above the top surface of said set plastic material, and a set plastic fill extending over the composite slab, the filler slab and the supporting element, the upwardly projectin portion of the structural members being em edded in said set fill.

17. A building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extending metallic structural members with a mass of set plastic material therebetween, the body of which extends below the bottom of said members, the ends of the structural members resting on and being supported by the supporting elements, and filler slabs between the spaced apart composite slabs and resting on the sides thereof, each of said metallic structural members having a portion projecting upwardly above the top surface of said set plastic material and extending toward the upwardly projecting portion of its neighbor, and a set plastic fill extending over the joint between a composite slab and a filler slab,

the upwardly projecting portion of each a structural member being embedded in said fill, the fill lying above and below that portion of the upwardly projecting portion of the metallic members which extends toward its nei hbor. a

18. building construction comprising main supporting elements forming a rectan- I gular bay, junior supporting elements ex-' tending between the main supporting elements, composite slabs comprising longitudinally extending metallic members, and a set mass of plastic material between and be-' low the same, the ends of each metallic member being supported by a supporting element,

and filler slabs supported between composlte slabs, and between a compositeslab and a main supporting element.

19. A building construction comprising main supporting elements forming a rectangular bay, junior supporting elements extending between the main supporting elements, composite slabs comprising longitudinally extending metallic members and a set mass of plastic material between and below the same, a portion of the metallic member projecting above the body of set plastic material, the ends of each metallic member being support ed by a supporting element, filler slabs supported between composite slabs and between a composite slab and a main supporting element, and a set fill overlying the main and junior supporting elements, the composite and filler slabs, a portion of the metallic members extending above the bod of set plastic material and embedded in sai set fill.

20. A building construction comprising vertical sustaining elements, main supporting elements connected thereto and forming a rectangular bay, junior supporting elements extending between the main supporting elements, composite slabs comprising longitudinally extending metallic members and a set mass of plastic material between and below the same, the ends of each metallic member being supported by a supporting element, filler slabs supported between composite slabs and between a composite slab and a main supporting element, and a poured-in-place mass of set plastic material adjacent to and contacting with the vertical sustaining element and extending between two main supporting elements, the side of a filler slab and the side of a composite slab.

21. A building construction comprising vertical sustaining elements, main supporting elements connected thereto and forming a rectangular bay, junior supporting elements extending between the main supporting elements, composite slabs comprising longitudinally extending metallic members and a set mass of plastic material between and below the same, the ends'of each metallic member being supported by a supporting element, filler slabs supported between composite slabs and between a composite slab and a main supporting element, and a poured-in-place mass of set plastic material adjacent to and contacting with the vertical sustaining element and extending between two main supporting elements, the side of a filler slab and the side of a composite slab, and a set fill covering the main and junior supporting elements, the composite and filler slabs, and the poured-in-place set plastic material.

22. A building construction comprising main supporting elements forming a rectangular bay, junior supporting elements extending between themain supporting elements, composite slabs comprising longitudinally extending metallic members, and a set mass of plastic material between and below the same, the ends of each metallic member being supported by a supporting element, and filler slabs supported between composite slabs, and between a composite slab and a main supporting element, the top and bottom surfaces of the set plastic material between the metallic members of the composite slabs, and the top and bottom surfaces of the filler slabs being in substantially the same plane respectively, the tops of the main and junior supporting elements being located between said planes.

23. A building construction comprising supporting elements, spaced apart precast slabs of inherently strong cementitious material supported at its endson said supporting elements, and precast filler slabs of inherently weaker material between the first mentioned slabs and supported thereby.

24. A precast slab of set plastic material having end flanges, a longitudinal metallic reinforcement therein, said reinforcement extending into said flanges and having its ends turned back into the slab.

:25. A precast slab of set plastic material having end flanges, a longitudinal metallic reinforcement therein, said reinforcement extending along the bottom portion thereof to a point near the slab ends, thence upwardly to a point substantially in line with the bottom of said flange and thence into the flange.

26. A precast slab of set plastic material having end flanges, a longitudinal metallic reinforcement therein, said reinforcement extending along the bottom portion thereof to a point near the slab ends, thence upwardly to a. point substantially in line with the bottom of said flange' and thence into the flange, the end of the reinforcement being turned back into the slab.

27. A precast slab of set plastic material having end flanges, a longitudinal metallic reinforcement therein, said reinforcement extending into said flanges along the bottom portion thereof so as to be substantially exposed there.

28. A precast slab of set plastic material having a series of reinforcements therein, and breaking grooves on the surface of said slab for breaking the slab between reinforce; ments so that each of said broken pieces may carry its reinforcement.

29. A precast slab of set plastic material having end flanges, a series of reinforcements in said slab and extending into the flanges, and breaking rooves on one face of said slab and on the corresponding face of the flange for breaking said slab between reinforcements, so that each of said broken pieces may carry its-reinforcement. v

30. As an article of manufacture a composite slab comprising a metallic member, having a vertical web and a base, and a set mass of plastic material above and below the base, a portion of the web of said metallic member projecting above the set mass.

31. As an article of manufacture a composite slab comprising two spaced apart metallic members, each having a flange at the top thereof, and a set mass of plastic material between said metallic nembers, the lower face of the top flange of each of said members being spaced from the said set mass.

32. As an article of manufacture a composite slab comprising two spaced apart metallic members and a set mass of plastic material therebetween, said mass extending below the bottom of said members and terminating short of the top thereof, the metallic members being of greater longitudinal extent than the body of set material, the bottom of the end portions of the metallic members being free of set lastic material.

33.' building construction including spaced apart supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extending metallic members with a mass of set plastic material therebetween, the ends of the structural members resting on and'being supported by the supporting elements and filler slabs between the spaced apart composite slabs and resting on the sides thereof, each of said metallic members having a portion projecting upwardly above the set material adjacent thereto, and a set plastic fill extending over the joint between a composite slab and a filler slab, the said projecting; portion of each structural element being embedded in said set fill.

34. A building construction including spaced apart i supporting elements, spaced apart composite slabs at right angles thereto, each slab comprising longitudinally extending metallic members with a mass of set plastic material therebetween, one of said metallic members having a portion projecting above the body of set plastic material and toward the other metallic member in said slab, the ends of the structural members rest-' tending metallic structural member having a vertical web and a bottom horizontal flange, and a set mass of plastic material, said mass extending beneath the bottom of said horizontal flange, and terminating short of the top thereof.

36. A building construction comprising supporting elements, spaced apart precast composite beams supported at their ends on said supporting elements, each composite beam including a longitudinally extending metallic structural member having a vertical web and a bottom horizontal flange, and a bodyof set plastic material beneath said flange, and filler slabs extending between composite beams.

37 A building construction comprising supporting elements, spaced apart composite beams supported attheir ends on said sup-, porting elements, each composite beam including a longitudinally extending metallic structural member having a vertical web and a bottom horizontal flange, and a body of set plastic material beneath said flange, and filler slabs extending between composite beams, the bottom of said filler-slabs being flush with the bottom of the set material beneath said structural member.

38. A building construction comprising supporting elements, spaced apart beams supportedat their ends on said supporting elements, and filler slabs extending between beams, the top of said filler slabs being below the to of said beams and the bottom of said slabs eing below the bottom of said beams, and a plastic fill overlying said beams and said filler slabs, the top of said beams being embedded in said fill.

39. A building construction comprising supporting elements, spaced apart beams each including a metallic structural member, said beams being supported at their ends on said supporting elements, and filler slabs extending between beams and resting on the metallic members below the top thereof, the top of said filler slabsbeingbelowthetopfofsaidstructural members and the bottom of said slabs being below the bottom of said structural members, said structural members having a flange at the top thereof, and a plastic fill overlying said beams and said filler slabs, the top flange of said structural members being embedded in said fill.

In testimony whereof, I have hereunto subscribed my name this 24th day of February, 

